Multiple-orientation wireless charging

ABSTRACT

A system includes a charging station and one or more receiving devices receiving wireless power from the charging station. The charging station includes an orientation adaptable antenna (OAA). The OAA may generate a magnetic field component parallel to the plane of the OAA to charge devices oriented at 90 degrees with respect to the OAA. The OAA may generate a magnetic field along different directions within the plane parallel to the OAA. The OAA may be able to adjust the direction of the field to couple to devices with antennas in different orientations. The OAA may further produce a magnetic field normal to the plane of the OAA. The OAA may adjust the relative strengths the various directional components of the magnetic field to align the field normal to the antennas of the receiving devices in up to three dimensions, simultaneously charge receiving devices in different orientations, or both.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to and thebenefit of U.S. patent application Ser. No. 14/871,074, filed Sep. 30,2015, which claims the benefit of and priority to U.S. ProvisionalApplication No. 62/148,352, filed Apr. 16, 2015, the contents of whichare hereby incorporated herein by reference in their entirety for allpurposes.

TECHNICAL FIELD

This disclosure relates to providing power wirelessly for multipledevice orientations.

BACKGROUND

Rapid advances in electronics and communication technologies, driven byimmense customer demand, have resulted in the widespread adoption ofmobile communication devices. Many of these devices, e.g., smartphones,have sophisticated processing capability and rely on clocks of differentfrequencies to perform different processing tasks, e.g., decoding andplayback of encoded audio files. These devices may rely on portablepower sources that are periodically charged. The ease and speed of thecharging process may contribute to the commercial success of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example wireless power environment.

FIG. 2 shows an example orientation adaptable antenna (OAA).

FIG. 3 shows example daisy chaining circuitry.

FIG. 4 shows an example macroblock tiled array.

FIG. 5 shows example power signal logic.

FIG. 6 shows a second example OAA.

FIG. 7 shows a third example OAA.

FIG. 8 shows a fourth example OAA.

FIG. 9 shows an example hybrid class power amplifier (HCPA).

FIG. 10 shows a second example HCPA.

DETAILED DESCRIPTION

The techniques and architectures discussed below facilitate wirelesspower provision for devices in many different orientations relative tothe charging station. For example, the antenna plane of the chargingantenna coil of the receiving device (the device which is wirelesslycharging) may be oriented orthogonal to the antenna plane of thecharging station. In the example, the receiving device may couple moreefficiently to a magnetic field parallel to the antenna plane of thecharging station than to a magnetic field normal to the chargingstation.

The charging station may also charge devices with antennas orientedparallel, orthogonal, or at other angles with respect to the antennaplane of the charging station. In the regard, the charging station maygenerate magnetic fields that run parallel to the antenna plane,orthogonal to the antenna plane, or at any other angle via asuper-position of magnetic fields at different orientations using anorientation adaptable antenna (OAA). The charging station may implementthe OAA via arrays of conductor traces, an antenna coil, magneticshielding layers, or any combination thereof.

The charging station may be configured to adjust the generated field toaccount for rotation of devices oriented, at least in part, in a planethat is orthogonal to the antenna plane of the charging device.

In some cases the coupling coefficient and current usage of the chargingstation may affect the performance of the charging station. For example,the coupling coefficient and current usage may affect the efficiency ofpower transfer. In an example scenario where the charging station isgenerating magnetic fields parallel to its antenna plane, the chargingstation may demonstrate higher efficiencies with a hybrid class poweramplifier (HCPA) that with class D or class E power amplifiers. The HCPAmay be driven in a signal ended circuit configuration or a double endedcircuit configuration.

FIG. 1 shows an example wireless power environment 100. The wirelesspower environment 100 includes portable devices 102 and 104, wearabledevices 106, and a charging station (CS) 110. The wireless powerenvironment 100 may include any number or type of devices. For example,Internet of Things (IoT) devices, such as building automation monitoringor control devices, home appliances, or any other device may be chargedor provided with operational power in the wireless power environment100. The techniques described below regarding wireless power may beimplemented in virtually any wireless power scenario. For example, thedevices 102-106 receiving the wireless power may charge a battery,capacitor, or other energy storage subsystem. Additionally oralternatively, the devices 102-106 may obtain the power needed fornormal operation directly from the power received from the CS 110.

The CS 110 may include power signal circuitry (PSC) 122 configured toselectively supply a power signal to any number of transmit coils, suchas the transmit coils 132, 134, and 136. The transmit coils 132-136transmit the power signals to the portable devices 102. The CS 110 mayinclude a power source 124 configured to support generation of thetransmitted power signals. The PSC 122 may convert a source signal fromthe power source 124 into a form that the antenna may transmit. Forexample, the source signal from the power source may provide a directcurrent (DC) or alternating current (AC) signal. The PSC 122 may includepower circuitry 126 which may tune the source signal from the powersource 124 to a particular frequency or signal level for transmissionvia one or more of the transmit coils 132-136 to the devices 102.

In various implementations, the CS 110 may include a transceiver 152 tosupport RF communication, one or more processors 154 to supportexecution of instructions, e.g., in the form of programs, and carry outoperation of the CS 110. The CS 110 may include memory 156 for executionsupport and storage of system instructions 168 and operation parameters162. In some implementations, the transceiver elements may receivestatus and/or control signals from the portable devices 102 and/orwearable devices 106. In some implementations, the CS 110 may usecontrol and/or status signals to adjust power signal parameters and/orother wireless power provisional strategies. For example, the signalsmay allow for detection of new devices within the power signal range,determination of when a device in range has completed charging, and/orother status or control determinations. For example, a device 102 may incommunication with the CS 110 over a wireless protocol, e.g. Bluetooth,Wi-Fi or other wireless protocol via transceiver 152. Additionally oralternatively, the CS 110 may monitor internal parameters for statusdetermination. For example, the load of any of the transmit coils132-136 may be monitored to determine the presence/absence of deviceswithin power signal range. For example, monitoring of internalparameters may be used by the CS 110 to support charging of a device 104which may not be in data communication with the CS 110. Thecommunication device may include a user interface 158 to facilitate foruser operation of the device.

In some implementations, the physical realization of the CS 110 mayinclude non-planar surfaces. For example, bowl-shaped stations,semispherical stations, pyramidal stations, or other CS shapes may beused. In some cases, a planar antenna design may be mapped on to thesurface topology of a non-planar CS. The resultant mapping may be usedto fashion a physical non-planar antenna on the surface of thenon-planar CS.

FIG. 2 shows an example OAA 200. The example OAA 200 may include anarray of traces 202, which may be metal traces, wires, or otherconductors. The OAA 200 may include one or more drivers 204 to sendcurrent through the traces 202. When current runs through the traces202, the traces generate a magnetic field. In the example OAA 200, thetraces 202 are disposed in parallel along the y-axis.

In some implementations, the traces 202 may be driven by amplifiercircuitry to generate a magnetic field that runs along the y-axis. Thetraces 202 may be driven coherently by the driver 204 to generate amagnetic field in the x-direction. Other field components (e.g., y-axis,z-axis field components) may be coherently cancelled by thesuperposition of the fields of the traces 202. In some cases, y-axis andz-axis components may not necessarily be fully cancelled by thesuper-positioning, which may allow coupling for devices with antennasoriented in these directions, e.g., oriented wholly or partially alongthe y-axis or z-axis. For example, non-x-axis fields may be generated atthe edges of the array formed by the traces 202. Additionally oralternatively, non-x-axis fields may be generated by traces that arecurved, not completely parallel, or in other configurations. Thedesignation of x, y, and z axes are relative designations which may bereferenced to the plane of the OAA, or defined in other ways. The CS 110drives the traces 202 to perform cancellation and coherent addition ofmagnetic field components to generate a total magnetic field (e.g., theresultant magnetic field after when the contributions from the tracesare accounted for) that may be oriented in a selectable direction.

Other coordinate systems may be used to describe the fields generated bythe system, e.g., polar coordinates, spherical coordinates, or other3-dimensional representations.

Additionally or alternatively, the example OAA 200 may include traces212 oriented along the x-axis. These traces may produce a magnetic fieldcomponent along the y-axis. The traces 212 may be driven by one or moredrivers 214.

When a device enters the charging field generated by the OAA 200, thedevice may not necessarily be fully aligned with the y-axis or thex-axis. The OAA 200 may adjust the relative driving levels of the traces202 to the traces 212 to generate a total magnetic field aligned withthe antenna plane of the charging antenna coil, for example, alignednormal to the charging antenna coil.

In some cases, the x-axis traces 212 and the y-axis traces 202 may bedriven independently, such that their fields super-position with littlecoherent interaction. Thus, the relative directional components of themagnetic field may be balanced independently to match the orientation ofthe device.

Additionally or alternatively, the x-axis traces 212 and the y-axistraces 202 may be driven by the CS 100 coherently with one another toeffect beam steering and focus of the magnetic field. Thus, coupling maybe directionally aligned by the CS 110 with the device and thedistribution across the OAA of the field may be adjusted such that thefield is concentrated at the position of the device or devices chargingon the CS 110.

Additionally or alternatively, an antenna coil 222 may be included inthe OAA 200. The antenna coil 222 may generate a z-axis field, e.g.normal to the page. The antenna coil 222 may be driven by one or moredrivers 224. The antenna coil 222 may surround the edges of the traces212, 202 (e.g., may include coil elements outside the traces 202 and212) or may be disposed within the grid defined by the traces 212, 202.

The relative driving of the x, y, and z axis magnetic field componentsby the two sets of traces 202 and 212, and/or the coil 222 may be usedby the CS 110 to align the magnetic field with the charging coil of thereceiving device in three dimensions (e.g., yaw, pitch, and roll).

Additionally or alternatively, the multiple-axis magnetic-fieldcomponents may be used to align the field to charge multiple devicesaligned to various planes. For example, a smartphone or tablet may layflat on the OAA and couple well to z-axis field components. A wearable,such as a watch, may have a wristband propping the wearable in anorientation about 90 degrees to the OAA. Thus, the traces 202, 212 maybe used by the CS 110 to generate a magnetic field parallel to the planeof the OAA to charge the wearable. The coil 222 may be used by the CS110 to generate a magnetic field normal to the OAA to charge thesmartphone, tablet, or other mobile device.

The trace 202, 212, and coil 222 may be separated by insulation, so thatthey may be overlapped without direct electrical coupling.

A CS 110 that includes an OAA 200 may establish a data communicationlink with a charging device over the transceiver 152. Using the datacommunication link the CS 110 may form a feedback loop with the chargingdevice. The PSC 122 of the CS 110 may cause the drivers 204, 214, 224 toadjust their current levels to vary the field direction or distributionuntil a desired charging level is achieved. In some cases, the feedbackloop may be used to perform a search for a maximum for chargingefficiency, (e.g., ratio of charging level to energy consumed by theOAA).

In an example scenario, the CS 110 may establish a data link with thecharging device, e.g., via Wi-Fi, Bluetooth, radio frequencyidentification (RFID), near-field communication (NFC), a personal areanetwork, or other wireless link. The charging device may send dataframes to the CS 110. The data frame may include status messages withindicators that allow the CS 110 to determine the charging status of thecharging device. The charging status may include battery levels or othercharging progress indicators; an indicator of charging rate, such as acurrent level in the charging device driven by the generated magneticfield; or other charging indicators. In some cases, a specific protocolmay be implemented by the CS 110 and the charging device where theorientation of the generated magnetic field may be varied to find a peakvalue in the driven current in the charging device or to obtain a drivencurrent above a threshold value. The charging device may indicate whencharging completes by sending completion data frame over the data link.

In some implementations, the charging device and the CS 110 may exchangepositioning data, such as location, orientation, or alignment. Forexample, the charging device may send global positioning information,such as, compass readings, magnetometer readings, accelerometerreadings, global positioning system readings or other positioning data.Additionally or alternatively, relative positioning data may beexchanged. For example multi-antenna charging devices and multi-antennacharging stations may use triangulation or beam steering to determinethe relative position (e.g., location, orientation, alignment) of thecharging device to the CS 110. Charging devices and the CS 110 may alsouse, radar, laser ranging, time of flight measurements, or other rangingschemes of determine the relative positions of the charging device tothe CS 110. Charging devices and the CS 110 may also use a line of sightanalysis of orientation markers, such as, radio emitters, infraredemitters or reflective surfaces, to determine the relative orientationor alignment of the charging device to the CS 110.

In some cases, the driver 204, 214, 224 may be separate drivers ordriver groups. However, the traces 202, 212 and coil 222 may be daisychained or otherwise electrically coupled to operate using a singledriver or single driver group.

In some cases, load sensing may be used by the CS 110 to select therelative driving for the field components. The coupling between thecharging antenna and the components of the OAA 200 (e.g., the traces212, 202, and coil 222) may affect the load on experience by drivers ofthese components. Applying load sensing schemes (resistivitymeasurements, r-sense, current measurements, or other load measurements)may allow the PSC 122 to determine the relative coupling for each of theantenna components and to adjust the driving levels accordingly.

The traces 202, 212 may be driven coherently by the CS 110. The coherentdriving may be achieved by multiple phase-locked drivers. For example,the traces may be driven by a group of drivers locked to the same clocksignal with defined offsets based on their effective distance (e.g., afunction of distance and the dielectric constant of the transmissionmaterial) from the signal source.

However, the traces 202, 212 may be daisy chained to be driven using asingle driver for multiple traces. In some implementations, returncurrent traces may be used to pass current between individual ones ofthe traces 202, 212 to complete the daisy chain. The return currenttraces may be disposed on a return current layer 240. The return currentlayer 240 may be separated from the layers containing the traces 202,212 by a shielding layer 230. Thus, the contribution to the field by thereturn current traces may be blocked by the shielding layer 230.

Moving now to FIG. 3, example daisy chaining circuitry 300, 350 isshown. The individual traces 202, 212 are paired with return traces 302,312. The effective length of the individual return traces 302, 312 maybe matched to the effective length of the traces 202, 212. Thus, thephase evolution across the individual traces 202, 212 may be undone whenthe current traverses the return traces 302, 312. Hence, the phase atthe start of the individual traces 202, 212 may be matched for the daisychained traces.

The return traces 302, 312 may create a symmetric field opposite to thetraces 202, 212. In some implementations, a shielding layer, e.g., aferrite layer or other shielding material, may be placed between thelayer including the traces and the layer including the return traces.For example, this may prevent the field from the return traces 302, 312coupling the field from the 202, 212.

In the example daisy chaining circuitry 300, the coil 222 is daisychained to the traces 212. However, in some cases, traces 212 may bedaisy chained and coil 222 may be driven independently. Further, in somecases, traces 202 and traces 212 may be daisy chained to one another.For example, daisy chaining circuity 300 may be output coupled to daisychaining circuitry 350. Virtually any combination of daisy chaining maybe used.

Different patterns of traces may be daisy chained. For example,alternating traces, e.g., every other trace or every ‘n’ traces, may bedaisy chained allowing for multiple drivers to control a group ofinterleaved traces. This may allow an additional degree of freedom indirecting and distributing the magnetic field.

In some cases, the OAA 200 may make-up a macroblock in a tiled-array ofmultiple OAAs. The tiled-array may implement charging device presencedetection as discussed above to determine which ones of the multiple OAAtiles are wirelessly coupled to an actively charging device. In somecases, the OAA tiles that are wirelessly coupled to actively chargingdevices may be activated while non-coupled tiles may be powered down.Thus, the tiled-array of OAAs may be scaled up in capacity to handlemultiple device charging, and may be scaled down to achieve efficientsingle/few device charging without active excess charging capacityconsuming power resources.

FIG. 4 shows an example macroblock 1002, 1004, 1006 tiled array 1000.The power signal circuitry 1022 may determine the presence of thecharging devices within the signal range of the macroblocks 1004, 1006.The macroblocks 1002 without devices in their signal range may bepowered down by the power signal circuitry 1022. For example, when thepower signal circuitry 1022 performs presence detection for a macroblock1002 and receives a negative result, the power signal circuitry maypower down the macroblock 1002. In some cases, a single device 102 maybe in the range of multiple macroblocks 1004. Additionally oralternatively a device 106 may be within the signal range of a singlemacroblock 1006.

When a device is within the signal range of multiple macroblocks 1004.The power signal circuitry may coordinate the driving signals sent tothe macroblocks 1004 to avoid interference among the macroblock signals.For example, the power signal circuitry may drive the macroblocks 1004coherently. Additionally or alternatively, the power signal circuitrymay select a single one or some subset of the group to charge the device102. In some systems, coordination of macroblocks may be implemented bythe powers signal circuitry 1022 whenever two neighboring macroblocksare active. For example, the power signal circuitry 1022 may coordinateneighboring macroblocks when the neighboring macroblocks are chargingdifferent devices or the same device.

The macroblocks 1002, 1004, 1006 are shown in a tiled array 1000 withspacing between the individual macroblocks other inter-macroblockspacings may be implemented. Further, in some implementations,contiguous macroblocks may make up the tiled array 1000.

FIG. 5 shows an example of power signal logic 400 that the CS 110 mayimplement in its circuitry. The power signal logic 400 may control thepower signal level used to drive an OAA. Further, the power signal logic400 control driving signal ratios among the traces to control thedirection of the generated magnetic field. The power signal logic 400may drive a first trace or group of traces to generate a magnetic field(402). The generated magnetic field may have one or more directionalcomponents. The power signal logic 400 may drive a second trace or groupof traces to generate additional field components (404). In some cases,the additional field components may combine additively or subtractivelywith the field components from the first trace, as discussed above, togenerate a magnetic field in a selectable orientation.

The power signal logic 400 may receive feedback from a charging device(406). For example, the power signal logic 400 may receive a fieldcoupling indicator over a data channel established between the CS 110and the charging device. Additionally or alternatively, the power signallogic may determine the coupling level based on the antenna loadimparted as feedback on the OAA by the charging device. The power signallogic 400 may determine a field coupling level for the charging deviceresponsive to the feedback (408). The power signal logic 400 may varythe driving ratios between the first and second traces to determinewhether the field coupling for charging device can be increased bychanging the field orientation, e.g., via the driving ratios between thefirst and second traces (410). The power signal logic 400 may determinewhen the field coupling has reached a selected level (412). For example,the power signal logic 400 may determine when a peak field coupling isreached, or find a field orientation that produces a field couplingabove a selected threshold. The power signal logic 400 may hold thegenerated field orientation while charging the charging device (414).The power signal logic 400 may also monitor the feedback to determinefield coupling level changes during charging (406). For example, theorientation of the charging device may be changed during charging. Thepower signal logic 400 may cease driving the traces when chargingcompletes (416). For example, charging may complete when the chargingdevice is removed from the CS 110 or when the charging device sendsfeedback indicating that a selected charge threshold has been reached,e.g., a target battery state or energy level.

Other OAA designs may be used to generate a directed field parallel tothe antenna plane. FIG. 6 shows views 500, 550 of a second example OAA.The second example OAA includes an antenna coil 502. The antenna coilincludes curved traces 512 that generate a field component parallel tothe coil 502. The curved traces 512 are interconnected with the lowerlayer traces 516 of the coil 502 by multi-layer interconnects 514. Thecurvature of the curved traces 512 also creates parallel fieldcomponents in multiple directions along the plane of the OAA. Thus, adevice oriented 90 degrees from the OAA may charge in a range oforientations. The coil 502 may also produce a field normal to the OAAplane. Thus, devices aligned parallel to the OAA may also be charged.The ratio of the parallel field strength to the normal field strengthfor the coil 502 may be adjusted based on the placement and thickness ofthe shielding layer 530. In some implementations, a ferrite shieldinglayer may be used. Two views 500, 550 of the second example OAA areshown. The first view 500 shows a transparent layer view showing thefull example antenna coil 502. The second view 550 shows the shieldinglayer 530 disposed between the curved traces 512 and the lower layertraces 516.

In an example scenario with ferrite shielding, the second example OAAwas implemented to create a field where the ratio of the normal to theparallel component (e.g., Hz/Hy) was 1.4. The system concurrentlydemonstrated a quality factor (Q) of 210. However, other configurationsare possible.

FIG. 7 shows views 600, 650 a third example OAA. The third example OAAincludes a rectangular coil 602. A shield 630 may be used with the thirdexample OAA. The rectangular coil produces a normal field component andparallel field components. Different shield thickness may be used. Inthe example, the shield is used to cover half the coil area. However,other positioning may be used. For example, a triangular shield may beused to cover coils such that the current in the exposed coils travelsonly one direction for each of the x and y axes. Two views 600, 650 ofthe third example OAA are shown. The first view 600 shows a transparentshielding layer 630 view showing the full example rectangular coil 602.The second view 650 shows the shielding layer 630 covering a portion ofthe rectangular coil 602.

Table 1 shows the ratios of the normal field component to the x and ycomponents for varying shield thicknesses and materials for the thirdexample OAA. Q values are also shown.

TABLE 1 Ratio of normal field component to parallel field components.Shield (thickness) Hz/Hx Hz/Hy Q No Ferrite 2.11 1.61 158 Ferrite (0.2mm) 1.87 1.59 158 Ferrite (0.4 mm) 1.81 1.56 156 Ferrite/Metal (0.2 mm)1.90 1.64 148

Moving now to FIG. 8, views 700, 750 a fourth example OAA is shown. Thefourth example OAA includes a circular coil 702. A shield 730 may beused with the fourth example OAA. The circular coil 702 produces anormal field component and parallel field components. A shield 730 maybe used to adjust the ratio of the normal field component to theparallel field component. Two views 700, 750 of the third example OAAare shown. The first view 700 shows a transparent shielding layer 730view showing the full example circular coil 702. The second view 750shows the shielding layer 730 covering a portion of the circular coil702.

In an example scenario a five turn circular coil of varying radius isused with a 50 mm radius ferrite shield. Table 2 show ratios of thenormal field component to the y component for varying coil width for theexample. Q values are also shown.

TABLE 2 Ratio of normal field component to parallel field component.Coil Radius (mm) Hz/Hy Q 5 1.69 267 10 1.63 259 15 1.51 240 20 1.36 14325 1.24 133 30 1.19 124

FIG. 9 shows an example HCPA 800. The HCPA 800 may be by the CS 110 tosupply a stable driving current to an OAA. The HCPA includessingle-ended driving circuitry 805. The hybrid class of the HCPA 800 mayallow currents of up to 1 A or more to be circulated through the OAA 200while holding the current level stable. In some cases, for a poweramplifier voltage (Vpa) of 10 V a target current of 1 A may be supplied.

The power amplifier circuitry 810 may be similar to a class E poweramplifier. For example, the power amplifier circuitry may includecapacitor Cs1 812, inductor Ls1 814, which may be present in class Epower amplifier designs. Additionally or alternatively, the poweramplifier circuitry 810 may include capacitor Cp2 816, which may bepresent in class D amplifier designs but not necessarily present inclass E amplifier designs. The power amplifier circuitry 810 may furthercouple to coil matching circuitry 820, which may allow for adjustment ofthe current flow to adapt to changing antenna impedance conditions. Insome cases, Cs1 812 and Ls1 814 may be used to match the carrierfrequency of the power signal. However, HCPA designs may also achievecarrier frequency tuning through adjustment of capacitor Cp2 816. Thus,Cs1 812 and Ls1 814 may be selected to match other parameters. Forexample, Cs1 812 and Ls1 814 may be selected for frequencies lower thanthe carrier frequency, modulation frequency, or another selectedfrequency characterizing the system. In some cases, tuning Cs1 812 andLs1 814 to a frequency below the carrier may assist in stabilizing theoutput power level of the system. Thus, the system may resist changingit power level output when changes to the antenna impedance occur. Cs1812 and Ls1 814 may be selected to allow for constant current over awide range of coil load impedances. The inclusion of Cs1 812 and Ls1 814selected for a low frequency resonance may also assist in mitigating theeffects of electromagnetic interference.

In some implementations, the complex impedance of Cs1 812 and Ls1 814may be matched (e.g., within a selected tolerance or approximatelymatched) to the complex conjugate of the impedance of Cp2 816. Further,in some systems, the roles of Ls1 814 and Cp2 816 may be inverted. Forexample, Ls1 814 may be used to achieve carrier frequency tuning, whileCp2 816 may be selected, along with Cs1 812, for low frequency. In somecases, Cs1 812 may be selected for fine impedance tuning and Ls1 814 maybe selected for coarse impedance tuning.

FIG. 10 shows a second example HCPA 900. The second example HCPA 900includes double-ended driving circuitry 905. The power amplifiercircuitry 910 may be similar to a class E power amplifier. The antennaload matching circuitry 920 may be similar to that of a class Damplifier.

In some cases, the HCPA 900 may be driven by pushing or pulling acurrent from a single one of the gates 906, 907. For example, a signalmay be supplied to one gate, which drives current through the HCPA.Signal may exit the other gate, but the signal need not be supplied tothe second gate.

The double-ended driving circuity 905 may allow for differential drivingfrom input gates 906, 907. In some cases, the current level supplied bythe HCPA may be adjusted by changing the relative phases of the drivingsignals on gates 906, 907. When two out-of-phase signals are combined athird signal at the frequency of the two signals is created. Theamplitude of the third signal depends on the phase offset between thetwo input signals. In some cases, performance gains, e.g., stability,efficiency, or other performance metrics, may be achieved over systemsthat vary the driving current by adjusting Vpa.

In some cases, an HCPA circuit (e.g., 800, 900) may be implemented inwireless power transfer environments where the generated EM-field mayhold more energy than used in some EM-fields used for signal transfer.To support the higher energy storage of the EM-field the HCPA circuitsmay drive a comparatively high current through the OAA. For example, thetarget current may be 1 A. In some cases, the coupling between the OAAand the charging device antenna may be low and the reflected impedancebetween the OAA and the charging device antenna may be low.

In some implementations, multiple power amplifier circuits (e.g., HCPA800, 900, or other power amplifier circuits) may be stacked, e.g., inparallel or series, to generate a higher power output than could becreated by any single one of the stacked power amplifier circuits. Theindividual stacked power amplifier circuitry may be activated ordeactivated to adjust to increasing or decreasing charging loads. Forexample, when a device is removed, and thus, decoupled from the CS 110,one or more power amplifier circuits may be deactivated. When a deviceis added, power amplifier circuits may be activated.

The methods, devices, processing, and logic described above may beimplemented in many different ways and in many different combinations ofhardware and software. For example, all or parts of the implementationsmay be circuitry that includes an instruction processor, such as aCentral Processing Unit (CPU), microcontroller, or a microprocessor; anApplication Specific Integrated Circuit (ASIC), Programmable LogicDevice (PLD), or Field Programmable Gate Array (FPGA); or circuitry thatincludes discrete logic or other circuit components, including analogcircuit components, digital circuit components or both; or anycombination thereof. The circuitry may include discrete interconnectedhardware components and/or may be combined on a single integratedcircuit die, distributed among multiple integrated circuit dies, orimplemented in a Multiple Chip Module (MCM) of multiple integratedcircuit dies in a common package, as examples.

The circuitry may further include or access instructions for executionby the circuitry. The instructions may be stored in a tangible storagemedium that is other than a transitory signal, such as a flash memory, aRandom Access Memory (RAM), a Read Only Memory (ROM), an ErasableProgrammable Read Only Memory (EPROM); or on a magnetic or optical disc,such as a Compact Disc Read Only Memory (CDROM), Hard Disk Drive (HDD),or other magnetic or optical disk; or in or on another machine-readablemedium. A product, such as a computer program product, may include astorage medium and instructions stored in or on the medium, and theinstructions when executed by the circuitry in a device may cause thedevice to implement any of the processing described above or illustratedin the drawings.

The implementations may be distributed as circuitry among multiplesystem components, such as among multiple processors and memories,optionally including multiple distributed processing systems.Parameters, databases, and other data structures may be separatelystored and managed, may be incorporated into a single memory ordatabase, may be logically and physically organized in many differentways, and may be implemented in many different ways, including as datastructures such as linked lists, hash tables, arrays, records, objects,or implicit storage mechanisms. Programs may be parts (e.g.,subroutines) of a single program, separate programs, distributed acrossseveral memories and processors, or implemented in many different ways,such as in a library, such as a shared library (e.g., a Dynamic LinkLibrary (DLL)). The DLL, for example, may store instructions thatperform any of the processing described above or illustrated in thedrawings, when executed by the circuitry.

Various implementations have been specifically described. However, manyother implementations are also possible.

1.-20.(canceled)
 21. An apparatus comprising: an antenna configured tocouple energy wirelessly to a charging device, the antenna comprising: afirst trace, when driven, configured to generate one or more firstmagnetic field components; and a second trace, when driven, configuredto generate one or more second magnetic field components, the one ormore first magnetic field components and the one or more second magneticfield components resulting in a magnetic field in a field orientation; acommunication interface configured to receive, from the charging device,a feedback indicating a field coupling between an antenna of thecharging device and the magnetic field; and power signal (PS) circuitryconfigured to vary a driving ratio between the first trace and thesecond trace to adjust the field orientation of the magnetic fieldresponsive to the feedback indicating the field coupling between theantenna of the charging device and the magnetic field.
 22. The apparatusof claim 21, wherein the antenna further comprises one or more driversconfigured to send current through the first trace and the second trace,and the PS circuitry varies the driving ratio between the first traceand the second trace by adjusting the current sent through the firsttrace and the second trace.
 23. The apparatus of claim 21, wherein theone or more second magnetic field components are combined additively orsubtractively with at least one of the one or more first magnetic fieldcomponents to generate the magnetic field in the field orientation. 24.The apparatus of claim 21, wherein the communication interface isconfigured to communicate with the charging device via at least one ofWi-Fi, Bluetooth, radio frequency identification (RFID), near-fieldcommunication (NFC), or a personal area network.
 25. The apparatus ofclaim 21, wherein the apparatus is a charging station, and the chargingstation comprises a planar surface.
 26. The apparatus of claim 21,wherein the apparatus is a charging station, and the charging stationcomprises a non-planar surface.
 27. A device comprising: power signal(PS) circuitry configured to wirelessly transfer energy to a chargingdevice; and an antenna comprising a plane of traces, the antennaconfigured to, when driven by the PS circuitry: generate a firstmagnetic field component parallel to the plane of traces; and generate asecond magnetic field component parallel to the plane of traces, whereinthe second magnetic field component is oriented in a direction differentfrom a direction of the first magnetic field component.
 28. The deviceof claim 27, wherein an antenna plane of the charging device is orientedorthogonally to the plane of traces.
 29. The device of claim 27, furthercomprising a transceiver configured to establish a communication linkwith the charging device via at least one of Wi-Fi, Bluetooth, radiofrequency identification (RFID), near-field communication (NFC), or apersonal area network.
 30. The device of claim 29, wherein thetransceiver is configured to receive a status or control messagecomprising a field coupling indicator for the charging device via thecommunication link.
 31. The device of claim 30, wherein the PS circuitryis configured to adjust power signal parameters, detect new chargingdevices within a power signal range, determine a battery level orcharging progress of the charging device, and determine when thecharging device has completed charging using information in the statusor control message.
 32. The device of claim 27, wherein the PS circuitryis configured to determine a field coupling for the charging device bymeasuring a load of the antenna.
 33. The device of claim 29, wherein thePS circuitry is configured to cause the antenna to adjust current levelsto vary a field direction or distribution until a predetermined charginglevel is reached using information received from the charging device viathe communication link.
 34. The device of claim 29, wherein the PScircuitry is configured to perform a search for a maximum for chargingefficiency for the charging device using information received from thecharging device via the communication link.
 35. The device of claim 29,wherein the transceiver is configured to receive positioning datacomprising at least one of location, orientation, or alignment from thecharging device.
 36. The device of claim 27, wherein: the plane oftraces comprises a plurality of macroblocks; and the PS circuitry isconfigured to: activate a first macroblock; and forgo activation of asecond macroblock when the first macroblock is coupled to an antenna ofthe charging device more strongly than the second macroblock.
 37. Asystem comprising: power signal (PS) circuitry configured to wirelesslytransfer energy to one or more charging devices; and an antennacomprising a plane of traces, the antenna configured to, when driven bythe PS circuitry: generate a first magnetic field component parallel tothe plane of traces; generate a second magnetic field component parallelto the plane of traces; and generate a third magnetic field componentnormal to the plane of traces.
 38. The system of claim 37, wherein thethird magnetic field component is used to charge a charging device whenan antenna plane of the charging device is oriented parallel to theplane of traces.
 39. The system of claim 37, wherein the first magneticfield component and the second magnetic field component are used tocharge a charging device when an antenna plane of the charging device isoriented orthogonally to the plane of traces.
 40. The system of claim37, wherein the plane of traces comprises first traces and secondtraces, the first traces, when driven, configured to generate the firstmagnetic field component parallel to the plane of traces, and the secondtraces, when driven, configured to generate the second magnetic fieldcomponent parallel to the plane of traces.
 41. The system of claim 40,wherein the antenna further comprises an antenna coil, which whendriven, is configured to generate the third magnetic field componentnormal to the plane of traces.
 42. The system of claim 41, wherein thefirst traces, the second traces, and the antenna coil are separated byinsulation.
 43. The system of claim 41, wherein the first traces aredaisy-chained with the second traces or with both the second traces andthe antenna coil.